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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

27857 results found.

  1. GRB 260903A: OHP/T193 optical afterglow detection
  2. NuSTAR Transient 260828: SOAR Optical Upper Limits
  3. SVOM GRB260903.53: Global MASTER-Net observations report
  4. GRB 260903A: LCO optical counterpart detection
  5. GRB 260827A: Insight-HXMT/HE detection
  6. EP260901a: SVOM/VT optical upper limits
  7. EP260901a: EP-FXT follow-up observation
  8. GRB 260829A: SVOM/GRM observation
  9. GRB 260818A: ATCA detection of a candidate radio counterpart
  10. EP260830a: EP-FXT follow-up observation
  11. EP260901a: Global MASTER-Net observations report
  12. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  13. NuSTAR Transient 260828: LCO Optical Upper Limits
  14. EP260901a: EP-WXT detection of a fast X-ray transient
  15. GRB 260830A: NuSTAR detection of prompt emission
  16. GRB 260831B: LCO optical upper limits
  17. EP260830a: Global MASTER-Net observations report
  18. EP260830a: EP-WXT detection of a fast X-ray transient
  19. GRB 260827A: SVOM/GRM observation
  20. NuSTAR 260828: a 1100s hard X-ray transient
  21. GRB 260831B: SVOM detection of a possible burst
  22. GRB 260827A: Glowbug gamma-ray detection
  23. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  24. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  25. GRB 260825A: SVOM/GRM observation of a long burst
  26. GRB 260829A: Fermi GBM Detection
  27. GRB 260825A: AstroSat CZTI detection
  28. GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
  29. IceCube-260827A: Upper limits from a search for additional neutrino events in IceCube
  30. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  31. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  32. GRB 260818B: Further EP-FXT observation
  33. GRB 260818B: VLT optical and nIR observations
  34. GRB 260818B: TNG NIR observations
  35. MAXI GRB260827.40: Global MASTER-Net observations report
  36. GRB 260818B: 6 GHz VLA observations
  37. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  38. GRB 260808B: SAO RAS observations of the optical rebrightening
  39. EP260822a: Global MASTER-Net observations report
  40. EP Alert 260820.31: Global MASTER-Net observations report
  41. GRB 260807A: EP-FXT follow-up observations
  42. IceCube Alert 260825A: Global MASTER-Net observations report
  43. IceCube-Cascade 260824A: Upper limits from a search for additional neutrino events in IceCube
  44. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  45. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  46. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  47. EP260822a: EP-FXT non-detection and upper limit
  48. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  49. EP260822a: Einstein Probe detection of a fast X-ray transient
  50. GRB 260822A: LCO optical upper limits
  51. GRB 260822A: GROWTH-India Telescope Upper Limits
  52. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  53. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  54. IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
  55. GRB 260818B: VLA radio observations
  56. GRB 260818B: SVOM/C-GFT optical upper limit
  57. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  58. IceCube Alert 260821A: Global MASTER-Net observations report
  59. GRB 260820A: Insight-HXMT/HE detection
  60. EP detected a brightening of LMXB 1ES 1735-26.9
  61. GRB 260818A: J-band observations with WINTER
  62. GRB 260818A: SVOM/ECLAIRs refined analysis
  63. GRB 260818B: NOT optical upper limits
  64. GRB 260810A: SVOM/GRM observation
  65. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  66. GRB 260818B: LCO optical upper limits
  67. GRB 260818B: SVOM detection of a short burst
  68. EP260806a: SAO RAS multicolor optical observations
  69. GRB 260818A: LCO optical upper limits
  70. EP260812a: AbAO optical upper limit
  71. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  72. GRB 260810A: Insight-HXMT/HE detection
  73. GRB 260818A: SVOM possible detection of a long and faint GRB
  74. EP260806a: NUTTELA-TAO optical observations
  75. The EP-WXT trigger 01709281429 is likely a flaring star
  76. EP260812a: AZT-22 optical upper limit
  77. EP260806a: WFST optical observations
  78. EP260812b: Optical upper limit with Kinder
  79. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  80. GRB 260808B: Liverpool Telescope further optical observations
  81. GRB 260813A: BALROG localization (Fermi Trigger 808341387 / GRB 260813803)
  82. EP260812a: NOT and Liverpool Telescope upper limits:
  83. EP260812b: Liverpool Telescope observations
  84. EP260812b: GOTO detection of the optical counterpart
  85. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  86. EP260812a: SVOM/C-GFT optical upper limit
  87. EP260812b: COLIBRÍ optical observations
  88. EP260812b: SVOM/VT optical observation
  89. GRB 260808A: SVOM/GRM observation
  90. EP260812b: Einstein Probe detection of an X-ray transient
  91. EP trigger #01709278129 (EP260812b?): NOT optical counterpart
  92. Fermi GBM Sub-Threshold Detection of GRB 260809A
  93. GRB 260810A: Glowbug gamma-ray detection
  94. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
  95. GRB 260810A: AstroSat CZTI detection of a long burst
  96. EP260812a: Einstein Probe detection of an X-ray transient
  97. GRB 260809A: SAO RAS optical observations
  98. GRB 260808B: SAO RAS optical observations
  99. GRB 260317A: SVOM/ECLAIRs detection through offline targeted search and its possible association to magnetar 1E 1841-04.5
  100. EP260806a: MAO/AZT-22 optical observations

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